Note 10 Employee Equity Incentive Plans (Tables)

12 Months Ended

Mar. 31, 2014

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Year Ended March 31,
Statement of Operations Classifications	2014		2013		2012
Cost of goods sold	$	457	$	398	$	376
Research, development and engineering		978		1,030		917
Selling, general and administrative		1,350		2,023		2,486
Stock-based compensation effect on income before taxes		2,785		3,451		3,779
Benefit from income taxes		1,071		1,287		1,375
Net stock-based compensation effects on net income	$	1,714	$	2,164	$	2,404

Schedule of Employee Service Share-based Compensation Fair Value Assumptions and Methodology [Table Text Block]

		Stock Options						Purchase Plan
		Year Ended March 31,						Year Ended March 31,
		2014		2013		2012		2014		2013		2012
Weighted average estimated per share
	fair value of grant	$	5.31	$	5.26	$	6.42	$	2.75	$	3.22	$	3.14
Risk-free interest rate			1.8%		1.1%		1.3%		0.1%		0.2%		0.2%
Expected term in years			6.05		6.34		5.85		0.50		0.50		0.50
Volatility			54.9%		55.3%		55.7%		37.0%		46.4%		51.6%
Dividend yield (1)			1.0%		0%		0%		0%		0%		0%
(1) Prior to October 1, 2013, the fair value of our equity awards was based on 0% dividend yield.

Schedule of Share-based Compensation, Stock Options Activity [Table Text Block]

	Stock compensation activity under our equity incentive plans for fiscal 2014, 2013 and 2012 is summarized below:
		Shares Available for Grant	Options Outstanding		Weighted Average Exercise Price per Share
			Number of Shares (1)	Intrinsic Value(2)
				(000)
Balances, March 31, 2011 (3)		1,102,786	5,199,768	$ 23,505	$ 9.03
	New shares authorized (4)	600,000	-
	Options granted	(966,000)	966,000		$ 12.37
	Options exercised	-	(478,264)	$ 2,862	$ 7.35
	Options cancelled	11,250	(164,500)		$ 8.30
	Options expired	-	(51,000)		$ 12.61
Balances, March 31, 2012		748,036	5,472,004	$ 19,532	$ 9.75
	Plan authorization expired	(589)	-
	Options granted	(455,000)	455,000		$ 9.93
	Options exercised	-	(153,131)	$ 443	$ 7.03
	Options cancelled	7,500	(67,425)		$ 8.34
	Options expired	-	(378,975)		$ 7.31
Balances, March 31, 2013		299,947	5,327,473	$ 4,273	$ 10.04
	New shares authorized (5)	2,000,000	-
	Plan authorization expired	(47,963)	-
	Options granted	(515,000)	515,000		$ 10.63
	Options exercised	-	(572,338)	$ 1,695	$ 8.72
	Options cancelled	24,000	(34,000)		$ 11.42
	Options expired	17,500	(34,500)		$ 12.62
Balances, March 31, 2014		1,778,484	5,201,635	$ 8,658	$ 10.22

(1) The number of stock options exercised includes shares that were withheld on behalf of employees to satisfy the statutory tax withholding requirements.

(2) Except for options exercised, these amounts represent the difference between the exercise price and $11.35 per share, the closing price of our stock on March 31, 2014 as reported on the NASDAQ Global Select Market, for all in-the-money, outstanding and exercisable options.

(3) Reflected the issurance of 151,766 restricted stock units prior to March 31, 2011.

(4) On September 16, 2011, our stockholders approved the 2011 Plan, under which 600,000 shares of our common stock are reserved for the grant of stock options.

(5) On August 30, 2013, our stockholders approved the 2013 Plan, under which 2,000,000 shares of our common stock are reserved for the grant of stock options.

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

Options Outstanding				Options Exercisable
Exercise Price per Share	Number of Shares Outstanding	Weighted Average Contractual Life	Weighted Average Exercise Price per Share	Number of Shares Exercisable	Weighted Average Exercise Price per Share
$5.01 - $7.75	1,023,897	4.5	$ 6.62	1,023,897	$ 6.62
$7.76 - $10.00	1,591,000	6.0	$ 9.26	997,000	$ 9.14
$10.01 - $12.50	1,680,950	6.3	$ 11.46	1,089,200	$ 11.29
$12.51 - $99.99	905,788	3.8	$ 13.65	755,788	$ 13.84
$5.01 - $99.99	5,201,635	5.4	$ 10.22	3,865,885	$ 10.00